Grey. The MINDER Ultra Thin Vibration Alarm is suitable for windows and doors features a 120dB alarm siren which sounds when false entry is attempted. The alarm siren will sound for approx. 25 seconds, and can be disarmed using the easy access on/off switch. It has a sleek slimline design at only 10mm thick and comes supplied with 3 x LR44 button batteries.. Alarm sounds when activated by vibration of window or door if false entry is attempted. 120dB alarm siren. Easy access on/off function. Attractive slimline design